Jack



J. L. HARPER JACK Original Filed May v1'7. 1922 Snom/woz Lfahn L. QZ/262 5 3 blickt/n I Patented Nov. 17, 1925.

UNITE-D (STATES vPATENT OFFICE.

JACK.

Application led May 17, 1922, Serial To all whom t may concern:

Be it known that I, JOHN L. HARPER, a citizen of the United States, and a. resident of Seattle, county of King, and State of Washington, have invented certain new and useful Improvements in Jacks, of which the following is a specification.

This invention relates to improvements in jacks,and particularly to jacks 'of that type especially desirable as an automobile, and truck accessory, and which embodies' in its construction a cylinder and a cylinder pis- 1n there is a normally closedby-pass valve,

located within a return flow channel between the cylinder and cylinder piston and which may be moved to open position by certain manipiilation of the pump rod connection so thatvthe jack may be lowered without inconvenience to `the operator Yand under the influence of the weight thereon. l

Other objects of the invention reside in uthe details of construction of the extension handleand pump mechanism, the 'cylinderpiston and its valve mechanism and in the means for actuating the by-pass valve.

In accomplishingr these and other objects ofthe invention, I- have provided the imroved details of construction. the preferred orms of which are illustrated in the accompanying drawings, whereini Figure 1 is a central, sectional view of a hydrostatic jack constructed'in accordance with the present invention; showing the pump handle in extended position.

Figure 2 is a side view of the same, with the handle collapsed.'` A

Figure 3 is a detail, sectional view, taken on the line 3-3 in Figure 1, and illustrating the dconnection of the handle with the jack hea Figures,- is a top view Vof the connection between the handle sections; showing the stop shoulders on the pivotally connected sections. l

No. 561,596. VRenewed March 25, 1925.

Figure 5 is a side view of a jack having a one-section handle.

Referring more in detail to the several views of the drawings- 1 designates the jack cylinder, and 2 a cylinder piston that is reciprocallv slidable therein and wherein a liquid pressure medium such as oil, water or glycerinemay be confined; the cylinder being providedat its lower end with an extended supporting base 3 and at its upper end is open and is eXteriorly threaded to receive a clamping ring 4 thereon whereby a packing washer 5, disposed beneath the ring, may be 'tightened against the'piston to preclude 'any possible leakage at theioint At its lower end, the cylinder-piston 2 is provided with a pump washer 6 which is held thereon by means of an overlying plate 7, and this, in turn, is tightened against the washer by means of nuts 8 and 9 that are threaded respectively ontoy the Vlower ends of tubes 10 and 11 that extend longitudinally through the piston and which open at their upper ends into channels 12 and 13 in ahead 14 which is formed upon and closes the upper end of the cylinder-piston; the tube 10 in this instance opens at its'lower end into the cylinder 1, while the tube 11 is closed at its lower end by the cap nut 9 and has an opening 15 into the piston, just above its bottom wall.; f

Both the channels 12 and 13 extend vertically within the head 1,4, and are connected at their upper ends by a horizontal channel 16 which leads into an annular channel 17 formed about the wall of a transverse bore 18 through the head. At the upper end of the channel 13 is a back check ball valve 20 whereby liquid pumped 'from the cylinder piston 2 through the tube 11 is prevented from returning, and located in the channel 16 is a ball check valve 21 whereby outward flow from cylinder 1 through tube 10 is prevented. Y The channels 12 and 13 are also connected, below the check valves, by a horizontal channel 22 wherein there is located a spring lpressed b v-pass valve 23, which normally prevents How from the channel 12 into 13.

The valve 23 has a stein 24, one end ofwhich extends from the head 14, as shown in Figure 1, and which may be pressed inward-f ly to unseat the valve to permit a flow' of llquid from cylinder 1 into piston 2.

The 1handle for the device, which formsl the pump cylinder, consists of two hingedly connected, tubular sections 26 and 27; the section 26 being tted at its innery end into a ,head 28 having a laterally extending, ta-

gered shank 29 fitted within the transverse ore 18 o the head 14 and secured therein by means of a nut 30 threaded onto the end of the Shank, as shown in Figure 3. The head 28 hasv a channel 31 communicating with the tube 26 and extended into the shank and opening laterally into continuous com- Lmunication with the annular channel 17 and .head channel 16.

end with a knob 39 whereby it may be ac-y tuated and about the outer end of the tube is an enlarged handle forming portion `40` and a packing ring 41 which prevents leakage. v

It is desirable in this construction, in order that the jack may be properly positioned beneath the axle of a vehicle, that the handle forming sections can be extended in 'a straight line, as shown in Figure 1, and retained substantially rigid. Then the operator may litt the jack from the outer end of the handle. 1n order to do this, yet atthe same time allow the sections to be broken downwardly, and .moved to the position shown in Figure 2, l have provided lugs 42 and 43 respectively on the adjacent faces of the elbows 33 and 34 which will engage each other when the sections extend in the same straight line.

In Figure 5, l have illustrated a jack having a single section handle which is of the same type of construction as the device of Figure l except that the handle section 27 is eliminated and the pump is applied within the section 26.

In order that one using the jack may, when it is desired, to lower the same, do this without necessitating his stooping over to press 'the valve stem 24,1 have mounted a pin 50 within the head 28, see Figures 1 and 3, which is slidable transversely therein and which has head. portions at its ends whereby it is retainedfrom being displaced. When it is desired to lower the jack, this pin 50 is shifted, to the dotted line position in Figure 3, so that when the handle section 26 is moved downwardly, as indicated in dotted lines in ligure 1, .the head of the pin will bear a instj the valve stein 24 to press it inwary and fr at the valve 23.

Assuming that the device is so constructed and assembled, it can be used in the following manner: The cylinder piston 2 is first lowered and is filled, by removing the plug 52 from a top opening 53 therein, see Figure 3, witha suitable Huid. The pump handle sections 26 and 27 are then extended, as shown in Figure 1, and by means of the handle, or otherwise, the jack is located beneath the object to be raised. 'lhen by reciprocating the pump rod 38, liquid will be drawn from the piston through tube ll and driven into cylinder 1 through tube l() and this will cause the piston to be lifted, return flow being prevented by the back check valves 20 and 21.

When it is desired` to lower the jat-lf, the handle is broken downwardly s'o that the pin 5() can be engaged with the valve stem 24 to unseat valve 23 and allow a ow of the liquid from the cylinder through tube 10, channel 22 and tube 11 into the cylinder-piston which will allow the latter to move downwardly accordingly as the quantity of oil in the cylinder is decreased.

It is readily apparent that jacks of this character can be used for all purposes and can be made in various sizes to suit the purposes for which they are intended.

lt is further apparent that such jacks can be stored in a very small space, are easy to operate and by their use, a person is able to lift loads that cannot be lifted by use or the ordinary types of geared jacks.

Having thus described myv invention, what I claim'as new therein and desire to secure by Letters-Patent, is:

1. A jack of the class described, comprising a base cylinder, a pist-on movable within the cylinder and extending therefrom, a pump tube pivotally connectedwith the piston, a piston operable within said tube whereby a liquid pressure medium may be pumped from Awithin the piston int/o the cylinder, a by-pass valve within the upper end of the plston having a stem extending therefrom, and means movable with the pump tube adapted to engage with the said stem to open the valve and permit a return flow of the liquid from the cylinder into the piston.

2. A jack of the class described, comprising a base cylinder, a Icylinder piston operable within the base cylinder and having a lifting head at its upper end, with channels therein having lower vend connections opening respectively into the cylinder and cylinder piston and having upper end connections with a cross channel, a putnp tube moimted pivotally at its .inner end in said head and having communication with the said cross channel, piston operable within the tube, checa valves in the channels whereby a fluid pressure medium may be forced, by operaa pumpl and tion of the pum from the piston into the cylinder to lift t e piston, a normally closed by-pass valve connectin the channels and having a stem extending from the head, and means movable with the pump tube, `en ageable with the said stem to unseat the va ve to allow a return flow from the cylinder into the piston.

3. A jack of the character described, comprising a base cylinder, a cylinder piston movable within the base cylinder with a liftin head at its upper end, having two vertica channels therein connected across their upper ends by a cross channel, tubes leading from the lower ends of said vertical channels, opening respectively into the cylinder and cylinder piston, a pump tube mounting having a laterally extended shank pivotally mounted in the lifting head for movement ofthe tube in a vertical plane, and. providing continuous communication between the pump tube and cross channel, a pumppiston in the said tube, back-check valves in the head channels whereby,.ufpon operation of the pumpI a liquid pressure medium may be forced rom the piston into the cylinder, a normally closed by-pass valve connectingA the vertical channels having a stem extending from the head, a pin mounted in the pump tube mountin movable to position to be engaged with the valve stem when the tube is moved downwardly to thereby unseat the valve to 'permit a return flow of the pressure medlum into the pistons. t

.4. A device as set forth in claim l, whereinthe ,pump tube consists of a plurality of pivotally connected sections for movement in vertical planes to be folded against the cylinder and wherein the pump piston is mounted within the outer end section.4

5. A device as in claim 4, wherein the sections of the pumpv tube"are provided with stop shoulders whereby their u ward, pivotal movement at the joint is limited and the `sections may be retained a ainst `farther movement when in a straight ine but may be broken downwardly at the joint.

Signed at- Seattle, -\Vashington, lthis 12th day of May, 1922.

, JOHN L. HARPER. 

